A source synchronization technology is a cross clock domain synchronization technology with a low delay, and is mainly applied to a process of data exchange between clock domains having a same source and a same frequency but different phases. A major technical principle of the technology is that a first clock domain simultaneously sends data and an echo clock signal (that is, a clock signal of the first clock domain) to a second clock domain; and the second clock domain writes the data according to the echo clock signal, and reads the written data according to a clock signal of the local domain (that is, a clock signal of the second clock domain). A specific implementation process may be shown in FIG. 1. The first clock domain simultaneously sends data and an echo clock signal to the second clock domain; a First In First Out (FIFO) buffer in the second clock domain regularly writes data at each beat; and then a D-type flip-flop (DFF) in the second clock domain regularly reads data at each beat according to a clock signal of the local domain. The echo clock signal has the same frequency as the clock signal of the second clock domain, and therefore the foregoing data reading method is feasible as long as a phase difference between the echo clock signal and the second clock domain is determined.
Currently, the phase difference may be determined using an associated data synchronization (Data Sync) signal. Referring to FIG. 2, the first clock domain generates a Data Sync signal for an echo clock signal, and the second clock domain may calculate, according to the Data Sync signal, a phase difference between a clock signal of the local clock domain and the echo clock signal. However, when a Data Sync signal is used, an input/output (I/O) interface that is used to transmit the Data Sync signal needs to be added, which increases hardware overheads. In addition, a phase relationship between a Data Sync signal and data needs to be strictly maintained during a signal transmission process, which increases difficulty of implementation.